Stage 1a2 lung cancer refers to early lung adenocarcinoma, which can be treated by resection surgery, but if recurrence and metastasis occurs after surgery, it may be related to the existence of cancer-causing genes, improper treatment and improper care. 1. Existence of cancer-causing genes: some lung adenocarcinoma patients have cancer-causing genes in their bodies, even if they have undergone surgery at early stage, there may still be gene mutation afterward, which may cause recurrence and metastasis. 2. Improper treatment: For patients with stage 1a2 lung cancer, if the surgery is not complete or the postoperative chemotherapy, targeted therapy or radiotherapy is not carried out in time, then recurrence or metastasis may occur. 3. Improper care: Lung cancer is a malignant tumor disease, which is easy to recur and metastasize. If patients do not pay attention to care after surgery and have various bad habits, such as smoking, drinking, overworking, etc., then the residual lung cancer cells will harm the immune system of the body, which will lead to recurrence and metastasis. Therefore, to deal with this disease, patients should have regular checkups, try their best to find it early and treat it as early as possible, eradicate it through surgery in time, and strengthen the post-operative care, maintain healthy living and dietary habits to reduce the risk of recurrence and metastasis.